JPH06347701A - Optical scanning type image input device - Google Patents

Abstract

(57) [Abstract] [Purpose] Even if the scanning range is changed by zoom conversion, the irradiation energy per unit area of the laser beam on the scanning surface of the sample does not fluctuate. Light equipment. [Structure] The irradiation light LB emitted from the light source 1 has its light quantity changed by the light quantity changing means 2, and the scanning means 6 scans the sample. Although the scanning range can be changed by the scanning range changing means 11, the light quantity of the light irradiating the sample 8 is determined by the light quantity detecting means 4.
The control means 12 maintains a constant light control regardless of the change in the size of the scanning range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic light control device. More specifically, the present invention relates to an automatic light control device which is provided in an optical scanning type image input device and which automatically adjusts the amount of irradiation light according to a change in scanning range.

[0002]

2. Description of the Related Art Recently, a sample is scanned with a laser beam like a laser scanning microscope, and reflected light or transmitted light from the sample or excited fluorescence is captured in accordance with the scanning light to form an image. The optical scanning type image input device is used. There is also a drawing device that processes the sample itself by scanning with a laser beam like a printer.

In this type of apparatus, the scanning range of the laser beam for scanning the sample surface is generally variable, and the two-dimensional scanning range is a magnification conversion called so-called zoom conversion in each of the X-axis direction and the Y-axis direction. Is done and fluctuates. As shown in FIG. 3, the maximum scanning range of the sample is a rectangle of length A and length B in the horizontal X-axis direction and the vertical Y-axis direction, respectively.
When the conversion rates are α and β in the X-axis direction and the Y-axis direction, respectively, the predetermined scanning range is a rectangle of length A ′ and length B ′, and A ′ = A / α and B ′ = B. / Β. For example, when the scanning time in the two-dimensional scanning range (one frame) is always constant, as in the case of forming an image at the video rate, the unit area of the laser beam is a constant intensity laser beam. The amount of irradiation energy per hit is inversely proportional to the area of the scanning range. It becomes larger when zoom conversion is performed and the conversion magnification increases. Here, the conversion rate is the product of the conversion rate α and the conversion rate β, α × β.

[0004]

However, as an example, when a sample is irradiated with a laser beam to capture excited fluorescence to form an image, first, the excitation light intensity is properly adjusted in the scanning range. Although the image formation is performed after adjustment, if the scanning range is reduced by zoom conversion after that, the irradiation energy per unit area may become excessive. Damage occurs when the irradiation energy per unit area becomes too large. The damage means that the sample is damaged by the irradiation of light, and the intensity of the excited fluorescence changes with time and is attenuated. If the irradiation energy per unit area is too large,
As shown in FIG. 4, the fluorescence intensity decays over time. However, if the irradiation energy per unit area is an appropriate magnitude, the fluorescence intensity is maintained constant over time, as shown in FIG. Thus, as the scanning range changes, the irradiation energy per unit area changes, and if it becomes too large, it may damage the sample and damage the sample during image formation, or the fluorescence intensity However, there was a problem that a good quality image could not be obtained due to fluctuation or decrease.

In view of the above problems, the present invention is provided in an optical scanning type image input apparatus in which the irradiation energy per unit area of the laser beam on the scanning surface of the sample does not change even if the scanning range is changed by zoom conversion. The object is to provide an automatic light control device.

[0006]

According to the present invention, there is provided a light source for emitting irradiation light, and a scanning means for scanning a sample with the irradiation light.
In an optical scanning type image input device having a scanning range changing means for changing the scanning range of the sample, a light amount changing means for changing the light amount of the irradiation light, and an irradiation light amount per unit area on the sample is the scanning range. Control means for controlling the light amount changing means in conjunction with the scanning range changing means so that the light quantity changing means maintains a constant value regardless of the change in the size.

It is desirable to have a light amount detecting means for detecting the irradiation light amount per unit area on the sample changed by the light amount changing means.

It is desirable that the irradiation light amount be controlled by the control means so as to be changed in inverse proportion to the size of the scanning range.

It is desirable to provide a fluorescence intensity measuring means for measuring the intensity of fluorescence emitted from the sample upon being excited by the irradiation of the irradiation light.

[0010]

The amount of irradiation light emitted from the light source is changed by the light amount changing means, and the sample is scanned by the scanning means. Although the scanning range can be changed by the scanning range changing means, the light amount of the light irradiating the sample is detected by the light amount detecting means and is kept constant by the control means regardless of the change of the size of the scanning range.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an optical arrangement of an embodiment relating to a laser scanning microscope. A light quantity converter 2 facing the exit end of the laser light source 1
Is provided. The light quantity converter 2 is a neutral density filter whose transmittance changes linearly or logarithmically depending on the rotation angle. It may be a liquid crystal filter whose transmittance changes according to the applied voltage. Light intensity converter 2
Next, a half mirror 3 for splitting the laser beam LB transmitted through the light quantity converter 2 is provided. The laser beam LB reflected by the half mirror 3 is received by the light amount detector 4 and its light amount is detected, and the laser beam LB transmitted through the half mirror 3 passes through the dichroic mirror 5 and travels toward the optical scanning mechanism 6.

The optical scanning mechanism 6 is composed of a vibrating mirror such as a galvanometer mirror or a resonance type galvanometer mirror. In the case of a resonance type galvanometer mirror, by applying a sinusoidal AC voltage, the vibrating mirror rotates and vibrates as shown by the arrow in the figure, and its amplitude is determined by the magnitude of the applied AC voltage. The vibrating mirror rotates about two axes. The objective lens 7 focuses the laser beam LB reflected by the optical scanning mechanism 6 on the sample 8 as a focusing lens. The fluorescence from the sample 8 excited by the laser beam LB enters the optical scanning mechanism 6 via the objective lens 7, is reflected again, is then reflected by the dichroic mirror 5, and is incident on the observation optical system (not shown). The observation optical system (not shown) is provided with a light amount detector 9 for detecting fluorescence intensity.

FIG. 2 is a block diagram showing the structure of the automatic light control circuit. The operation unit 10 includes a control panel and a keyboard, and outputs a command signal indicating a scanning range of the laser beam LB on the sample surface 8. Scan range converter 1
In response to a command signal from the operation unit 10, 1 controls the AC voltage applied to the optical scanning mechanism 6 to set the scanning range.
The CPU 12 receives a command signal from the operation unit 10 and outputs a drive signal to the light quantity converter 2 so that the light quantity per unit area becomes constant when the scanning range on the sample surface 8 is changed by the laser beam LB. Then, the intensity of the laser beam LB irradiated on the sample surface 8 is adjusted. Further CPU1
2 receives the output signal of the light quantity detector 4 and receives the laser light source 1
The intensity of the laser beam LB from is detected. Then, when the luminous intensity fluctuates, the light quantity converter 2 is driven so as to correct the fluctuation.

Next, the operation will be described. The laser beam LB emitted from the light source 1 passes through the light quantity converter 2, the half mirror 3 and the dichroic mirror 5, and then enters the scanning mechanism 6. The reflection mirror constituting the scanning mechanism 6 vibrates, the laser beam LB reflected by the scanning mechanism 6 is condensed by the objective lens 7, and then scans the surface of the sample 8.
The scanning range is in the X-axis direction and the Y-axis direction, and the operation unit 10
It is set by the control panel or keyboard of.

The fluorescence excited by the laser beam LB from the sample 8 enters the light quantity detector 9 through the objective lens 7, the optical scanning mechanism 6 and the dichroic mirror 5, and the fluorescence intensity is detected. If the sample 8 has information about damage in advance, set an appropriate excitation light intensity from the beginning,
The fluorescent image can be observed. However, when there is no information, the scanning range of the laser beam LB is first determined, and the sample 8
Instead of the monitor, a monitor is used to investigate whether or not the excitation light intensity is excessive and the damage as shown in FIG. 5 is caused, and as shown in FIG. 4, the fluorescence intensity is adjusted so as not to change with time. Alternatively, it is necessary to adjust the excitation light intensity while softly checking the change in fluorescence intensity. At this time, it is desirable to select a rectangle having the length A and the length B of the maximum scanning range of the sample shown in FIG. 3 as the initial scanning range. This is because the adjustment of the light quantity converter 2 according to the scanning range can be performed only in the dimming direction, and the adjustment is easy and there is no risk of damage.

On the other hand, when an appropriate excitation light intensity is obtained by adjusting the light quantity converter 2, a part of the laser beam LB emitted from the light source 1 is reflected by the half mirror 3 and is incident on the light quantity detector 4, and the light quantity is changed. The information on the detected light quantity I at this time is output from the light quantity detector 4 to the CPU 12 and stored therein.

Next, the operating section 10 is operated to change the scanning range. First, a rectangular scanning range of length A and length B will be described as an example. When the magnification conversion rates are α and β in the X-axis direction and the Y-axis direction, respectively, the predetermined scanning range has a length A ′.
And a rectangle of length B ', where A' = A / α and B '= B /
Beta. The information on the change of the scanning range is output to the CPU 12, and the light amount I in the scanning range of the length A and the length B is changed to the light amount I / α × β in the scanning range of the length A ′ and the length B ′. Thus, the drive signal is output to the light quantity converter 2. Then, the intensity of the excitation light on the sample surface 8 is kept constant, the intensity of the excitation light is not excessive and does not damage the sample, and the intensity of the excitation light is too small to excite the sample sufficiently. There is no problem that the fluorescence image of is not obtained.

Although the laser scanning microscope has been described in this embodiment, it is needless to say that the other light scanning type image input device and drawing device can similarly perform automatic light control.

[0019]

As described above, according to the present invention, the amount of irradiation light emitted from the light source is changed by the light amount changing means and the sample is scanned by the scanning means. Although the scanning range is variable by the scanning range changing means, the light amount of the light irradiating the sample is detected by the light amount detecting means, and is kept constant regardless of the change in the size of the scanning range by the control means.
A good quality image can always be obtained without damaging the sample.

[Brief description of drawings]

FIG. 1 is an optical layout diagram of a laser scanning microscope according to an embodiment of the present invention.

FIG. 2 is a block configuration diagram of an automatic light control circuit of a laser scanning microscope according to an embodiment of the present invention.

FIG. 3 is a diagram showing a scanning range of a sample according to an embodiment of the present invention.

FIG. 4 is a diagram showing a temporal change (damage) in fluorescence intensity.

FIG. 5 is a diagram showing a temporal change (damage) in fluorescence intensity.

[Explanation of symbols]

 1 ... Laser light source 2 Light intensity converter 3 Half mirror 4 Light intensity detector 5 Dichroic mirror 6 Optical scanning mechanism 7 ... Objective lens 8 ・ ・ ・ ・ Sample 9 ・ ・ ・ Light intensity detector 10 ・ ・ ・ ・ Operation part 11 ・ ・ ・ ・ Scanning range converter 12 ・ ・ ・ ・ CPU LB ・ ・ ・ ・ Laser beam

Claims (4)

[Claims] 1. An optical scanning type image input device comprising: a light source for emitting irradiation light; a scanning unit for scanning a sample with the irradiation light; and a scanning range changing unit for changing a scanning range of the sample. Light amount changing means for changing the light amount of the light, and linked with the scanning range changing means so that the irradiation light amount per unit area on the sample is maintained constant regardless of the change of the size of the scanning range. An optical scanning image input device comprising: a control unit that controls the light amount changing unit. 2. The optical scanning type image input device according to claim 1, further comprising a light amount detection unit for detecting an irradiation light amount per unit area on the sample changed by the light amount changing unit. 3. The optical scanning image according to claim 1, wherein the irradiation light amount is controlled by the control means so as to be changed in inverse proportion to the size of the scanning range. Input device. 4. The light according to claim 1, further comprising fluorescence intensity measuring means for measuring the intensity of fluorescence emitted from the sample upon being excited by the irradiation of the irradiation light. Scanning image input device.